Oracle Database - Gateway Data Dictionary

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1 - About

This article contains informations about the metadata of Gateway.

When the gateway agent access the database through an agent (ODBC, …), the data dictionnay from the remote database are stored in the Gateway Data Dictionary Views which start with HS.

SELECT * FROM all_objects WHERE object_name LIKE 'HS_%'

Both the server and the agent rely on three types of information to configure and control operation of the Heterogeneous Services connection. These three sets of information are collectively called HS configuration data:

  • Heterogeneous Services initialization parameters: Provide control over various connection-specific details of operation.
  • Capability definitions: Identify details like SQL language features supported by the non-Oracle data source.
  • Data dictionary (translations) from the remote database to the Oracle Data Dictionary.

3 - Views

Map references to Oracle data dictionary tables and views into equivalents specific to the non-Oracle data source.

The documentation split the view in two categories:

View Type Identifies
HS_BASE_CAPS SQL service All capabilities supported by Heterogeneous Services
HS_BASE_DD SQL service All data dictionary translation table names supported by Heterogeneous Services
HS_CLASS_CAPS Transaction service, SQL service Capabilities for each class
HS_CLASS_DD SQL service Data dictionary translations for each class
HS_CLASS_INIT General Initialization parameters for each class
HS_FDS_CLASS General Classes accessible from the Oracle server
HS_FDS_INST General Instances accessible from the Oracle server
HS_INST_CAPS Transaction service, SQL service Capabilities for each instance (if set up by the DBA)
HS_INST_DD SQL service Data dictionary translations for each class (if set up by the DBA)
HS_INST_INIT General Initialization parameters for each instance (if set up by the DBA)
HS_BULK Data dictionary view to keep track of internal objects created with bulk load procedures.
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